Telescope Germanium Vertical Telescope Germanium Vertical JINR Dubna, Russia CSNSM Orsay, France CTU Prague, Czech Republic RRC - Kurchatov Institute Moscow, Russia CU Bratislava, Slovakia status report V. Egorov

Double Beta Spectrometers

Nuclei - candidates 0.187% 1.25% 2 X-rays $ 0.25 ×10 6 /g

TGV-1 (1994 – 2000) results T 1/2 (2  2 ) = =(2.9  7.5)10 19 y T 1/2 (2  0 )   y (90%CL) Zero

Telescope Germanium Vertical (TGV-2) Telescope Germanium Vertical (TGV-2) 32 HPGe planar detectors  60 mm × 6 mm with sensitive volume: 20.4 cm 2 × 6 mm Total sensitive volume: ~400 cm 3 Total mass of detectors: ~3 kg Total area of samples : 330 cm 2 Total mass of samples : 10  25 g Total efficiency : 50  60 % E-resolution : 3  4 60 Co LE-threshold : 5  6 keV Double EC ( ): - 12 samples of 106 Cd: 10 g 106 Cd (~ 50 µm ) U+Th<0.1 ppb

TGV-2 (2000 – …)

High freq. noise: E1 > E2 Real signal: E1 = E2 Low freq. noise: E1 < E2 Suppression of low energy noise with primitive Fourier analysis

Low frequency (microphonic)

νGEMMA search for the Neutrino Magnetic Moment BTW:

Low Energy Threshold [keV] ~ measurement quality µ [ 10 –10 µ B ]

Results of one-year (2005) measurement 2νEC/EC (0+→0+,g.s.) decay of Cd-106 Experiment T 1/2 ≥ 1.8 x y (95%CL) (TGV-2) T 1/2 ≥ 5.8 x y (90%CL) (F.Danevich et.al.) T 1/2 ≥ 1.5 x y (68%CL) (H.Kiel et.al.) Theory T 1/2 = 1.0 x y (J.Suhonen) T 1/2 = 8.7 x y (M.Hirsch) T 1/2 = 4.4 x y (F.Simkovich)

 -line 238 keV Counts / day /detector  -line 352 keV Counts / day /detector

Gas-tight cup of the cryostat (ultra-pure Al, made by CANBERRA) has a weld seam here

Drastic solution

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2νEC/EC (0+→0+,g.s.) decay of Cd-106 Experiment T 1/2 ≥ 1.8 x y (95%CL) (TGV-2) T 1/2 ≥ 5.8 x y (90%CL) (F.Danevich et.al.) T 1/2 ≥ 1.5 x y (68%CL) (H.Kiel et.al.) Theory T 1/2 = 1.0 x y (J.Suhonen) T 1/2 = 8.7 x y (M.Hirsch) T 1/2 = 4.4 x y (F.Simkovich) Comparision of results

Muon Capture Rates for Double Beta Decay ( PSI experiment R02-02 )  CR42 

 (d, 2 He) [ PR C70(2004) ]

Ordinary Muon Capture (OMC) Electron Capture: e - + (A,Z)  (A, Z-1) + e Q ~ m e  0.5 MeV Muon Capture:  - + (A,Z)  (A, Z-1) +  Q ~ m   100 MeV  CR42 

OMC

Set-up

Observables measured:  -radiation energy ( keV) Time between the µ-Stop and the  -emission ( ns)

Energy of gamma-rays [keV] Time after the Muon Stop [ns]

Data Analysis: Time evolution of the  -lines intensity Muon Life Time in the given isotope µ-Capture Rate in the given isotope

48 Ca 599±2 ns 48 Ti 360±1 ns 40 Ca 362±2 ns Total  -Capture Rates  CR42 

Data Analysis: Intensity of the  -lines in the intermediate nucleus Detailed balance of the  -intensities Partial µ-capture rates to the (1 + ), (2 – ) and other (low) excited states of the intermediate nucleus

OMC  CR42 

Data Analysis: Intensity of the  -lines of the other daughter nuclei Yield of the different daughter nuclei Branching of the reactions: (µ, ) (µ, n) (µ, 2n) (µ, p) … Population of high-excited states in the intermediate nucleus

 -lines observed with 76 Se target

BTW: µ – stopped in Argon Long-lived nuclei produced by µ – -capture in Ar T , Q [keV] Yield [%] per stopped muon 40 Ar(µ –, µ ) 40 Cl 1.35m ± Ar(µ –, µ n) 39 Cl 39 Cl → 39 Ar 55.6m d ± Ar(µ –, µ 2n) 38 Cl m 0.72s (IT)1.64 ± Ar(µ –, µ 2n) 38 Cl 37.2m ± 0.57 Λ capture =(1.165±0.013) 1/µs (Could be important for GERDA)

Status of the µCR42β experiment 2β2β 48 Ca 76 Ge 82 Se 100 Mo 106 Cd 116 Cd 150 Nd µC- target 48 Ti 76 Se 82 Kr 100 Ru 106 Cd 116 Sn 150 Sm Expe- riment — Ana- lysis done In pro- gress —In pro- gress —Star- ted